<!DOCTYPE html>
<html>
  <head>
    <style>
      label {color: red}
      #one[disabled]:not(:enabled) + label {color: green}
      #two:not([disabled]):enabled + label {color: green}
    </style>
  </head>
  <body onload='var elem = document.getElementById("one");
                elem.setAttribute("disabled", "disabled");
                document.getElementById("two").removeAttribute("disabled")'>
    <div>
      <input id="one"/>
      <label for="one">Should be no red</label>
    </div>
    <div>
      <input id="two" disabled="disabled"/>
      <label for="two">Should be no red</label>
    </div>
  </body>
</html>
